Method for the manufacture of an anti-sweat water closet tank



March 25, 1969 ,J. K. BOORMAN METHOD FOR THE MANUFACTURE OF AN ANTI-SWEAT WATER CLOSET TANK Filed Nov. 2'7, 1964 FIG. 3

INVENTOR. John Kori Boorman FIG.4

ATTORNEY United States Patent 3,435,101 METHOD FOR THE MANUFACTURE OF AN ANTI- SWEAT WATER CLOSET TANK John K. Boorman, Don Mills, Ontario, Canada, assignor to American Standard Inc., New York, N .Y., a corporation of Delaware Filed Nov. 27, 1964, Ser. No. 414,319 Claims priority, application Canada, Jan. 30, 1964, 894,148 Int. Cl. 132% 9/00 US. Cl. 264-45 11 Claims ABSTRACT OF THE DISCLOSURE Method for forming a synthetic resin lining on the inner side and bottom surfaces of a toilet fiush tank having a bottom, four side walls and an open top which comprises the steps of inserting a self-expanding synthetic resin mixture into the tank, placing a core of the same general configuration as the tank having outer side and bottom surfaces within and in spaced apart relationship to the tank to form a cavity between the inner surfaces of the tank and the outer surfaces of the core, allowing the synthetic resin mixture to expand to fill the cavity.

This invention relates to a new and improved method for lining tanks or hollow articles and more particularly for lining toilet flush tanks.

It is well known in the art that objectionable sweating (dripping of condensate) from toilet flush tanks may be eliminated or minimized by providing a suitable insulating lining in the flush tank.

Heretofore a synthetic resin liner has been formed on and integral with the inner surfaces of a flush tank by using conventional expanded in place by application of heat techniques.

The presently known method of forming a synthetic resin liner integrally with a flush tank involves the use of a steam chest or the like as a hollow core, to introduce heat in close proximity to the synthetic resin materials to cause them to expand. This technique necessitates the use of cumbersome steam fittings and leads to and from the apparatus used to form the lining. The method is inefiicient and costly.

It is the principal object of this invention to provide a method for forming a synthetic resin lining on and integral with the inner side and bottom surfaces of a toilet flush tank having a bottom, four side walls and an open top.

Another object of the invention is to provide for a method of forming a tank liner with a flush tank that does not require the application of heat.

According to this invention the method for forming the tank liner includes the steps of inserting a self-expanding synthetic resin mixture into the tank, placing a core of the same general configuration as the tank having outer side and bottom surfaces within and in spaced apart relationship to the tank, to form a cavity between the inner surfaces of the tank and the outer surfaces of the cone, allowing the synthetic resin mixture to expand to fill the cavity, removing the core.

Further features of the invention include: covering the core with a parting agent prior to inserting it into the tank; securing spacers by means of adhesive on the inner surfaces of the tank to establish the spaced apart relationship of the core and the tank; sealing all apertures in the inner side and bottom surfaces of the tank; using an expansible core that has an outstanding perimetrical step containing a vent at its top edge; inserting at least one wedge in the core to expand it causing its stepped perimetrical top edge to press firmly against the inner surfaces of the tank ice creating a perimetrical upper limit to the cavity and fixing the core in the tank.

The invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is an exploded perspective view showing a toilet flush tank, a core and wedges prior to assembly within the tank, the toilet flush tank is partially broken away to also show a means for sealing apertures in the tank;

FIGURE 2 is a vertical sectional view of a toilet flush tank showing a synthetic resin mixture being poured into the tank.

FIGURE 3 is a vertical sectional view of a toilet flush tank, expansible core and wedges, as assembled, showing a synthetic resin lining formed in place;

FIGURE 4 is a perspective view of a toilet flush tank containing a synthetic resin lining, being the finished product after the core and wedges have been removed.

Referring now to FIGURE 1, a toilet flush tank 1 has oppositely disposed walls 2, 2 and 3, 3 and a bottom 4. In one of the walls there is a rectangular opening 5, and in the bottom 4 are two circular openings 6 and 7 for pipes. The tank is prepared for lining by securing, by means of adhesive, a number of cork or rubber spacers 8 to the inside surfaces of walls 2, 2 and bottom 4, and by sealing openings 5, 6 and 7 on the inside with masking tape 9. The thickness of the spacers establishes the thickness of a synthetic resin lining 19 (as shown in FIG- URE 3).

An expansible core 10, constructed of epoxy resin and fibreglass or the like, has oppositely disposed walls 11, 11 and 12, 12 and a bottom 13. The outer surfaces of each of the walls 11, 11 and 12, 12 are olfset outwardly to form a stepped perimetrical top edge 14 in which there are a number of vents 14a. In each of walls 12, 12 there is a vertical slot 15, which allows the core 10 to be expanded or contracted to vary the distance between walls 11, 11. On the inside surface of each wall 12, 12 there is a shield 16 covering slot 15. The core is prepared for insertion into the tank by covering the outer surface of walls 11, 11 and 12, 12 and bottom 13, with a suitable parting agent such as wax.

Referring to FIGURE 3, the oppositely disposed walls of flush tank 1 taper slightly from the top to the bottom of the tank. The expansible core 10 has the same tapered configuration so that it will nest within the tank. The inner and outer surfaces of core 10 are essentially parallel and thus have the same taper. The outer dimensions of the stepped perimetrical top edge 14 are essentially the same as the dimensions for those portions of the inner surfaces of tank 1 that adjoin the stepped perimetrical top edge of the core when the core and tank are assembled as shown in FIGURE 3. The tolerances for these dimensions of the core are not extremely critical due to the expansible character of the core. Because of spacers 8 and perimetrical top edge 14, when the core 10 is inserted in the tank 1, a cavity is formed between the outer surfaces of walls 11, 11 and 12, 12, and bottom 13 of the core, and the inner surfaces of walls 2, 2 and 3, 3 and bottom 4 of the tank.

To ensure that the core 10 will maintain its position when inserted into the tank 1, one or more wedges 17, as shown in FIGURE 1, are forcibly positioned within the core 10 with their edges 18 abutting against the inner surfaces of walls 11, 11 as shown in FIGURE 3. The wedges 17 have a taper that coincides with the taper of the core and the tank. The insertion of the wedges results in expansion of the core, due to the presence of slots 15, causing its stepped perimetrical top edge to press firmly against the inner surfaces of the tank walls 2, 2 creating a perimetrical upper limit to the cavity formed between the inner surfaces of the tank walls and the outer surfaces of the core walls, and fixes the core in the tank.

Referring to FIGURE 2, the synthetic resin lining 19 is formed by expansion, within the cavity created by the core and the tank, of a foamable poly-urethane mixture 20, that is poured into the tank 1 prior to insertion of the core 10. The foamable poly-urethane is an isocyanate and hydroxy compound. The tank lining which is polyurethane foam is the reaction product of the isocyanate and hydroxy compound, expanded by carbon dioxide, which is liberated by water-isocyanate reaction, or by low boiling halogenated hydrocarbons, or both. The reaction speed, and the physical properties of the poly-urethane foam are controlled by catalysts, surface acting agents, and pH adjusting agents.

Many commercially known foamable poly-urethane compounds are suitable for applying the method of the present invention. The invention has been successfully practiced with a poly-urethane compound comprising two components. One of the components is made up of 93.5% prepolymer which is a reaction product of 78% toluene diisocyanate and 22% polyoxypropylene sorbital (Hydroxyl No. 490), 6% monofiuorotrichloromethane (commercially known as Freon 11) and 0.5% silicone L520 (this is the trade name designation of a product of Union Carbide Canada Limited). The other component is made up of 73.7% polyoxypropylene sorbital (Hydroxyl No. 490), 0.5% triethylene diamine (commercially known as Dabco catalyst), and 25.8% Freon 11. In preparing a synthetic resin charge for lining a toilet flush tank as herein referred to, 12 ounces of each component are thoroughly mixed together and poured evenly down the inner surface of the prepared tank 1. The mixture starts to foam in approximately 20 seconds. It will be understood of course that the quantity of synthetic resin charge used will be different for lining tanks of different sizes.

In accordance with the method of the present inven tion, into the tank 1, to which has been secured spacers 8 and whose openings 5, 6 and 7 have been sealed with masking tape 9, is poured, in the prescribed way, the charge of polyurethane. A core 10, that has been covered with the wax parting agent, is immediately inserted into the tank, positioned to abut against the spacers 8. When the core has been positioned in the tank, one or more of the wedges 17 are forcibly positioned within the core causing its stepped perimetrical top edge to press firmly against the inner surfaces of the tank to create the perimetrical top limit to the cavity. After having allowed the poly-urethane mixture to expand to fill the cavity, thus forming a lining integral with the inner surface of the tank, the wedges are removed. The core is contracted to break surface tension between the core and the lining material, and the core is removed from the tank. Any excess lining material, which has been extruded by the expansion pressure of the poly-urethane mixture through the vent holes 14a, is trimmed flush with the top edge of the lining that is created by the stepped perimetrical top edge of the core. The masking tape is removed from the openings and a lined tank results as shown in FIG- URE 4.

What is claimed:

1. A method for forming a synthetic resin lining on the inner side and bottom surfaces of a toilet flush tank having a bottom, four side walls, and an open top comprising the steps of inserting a self-expanding synthetic resin mixture into the tank, placing an expansible core of the same general configuration as the tank having outer side and bottom surfaces and an outstanding perimetrical step at its top edge in which there is a vent, within and in spaced apart relationship to the tank to form a cavity between the inner surfaces of the tank and the outer surfaces of the core, allowing the synthetic resin mixture to expand to fill the cavity, and removing the core.

2. A method as claimed in claim 1 in which the core is covered with a parting agent prior to inserting it into the tank.

3. A method as claimed in claim 2 in which spacers are secured by means of adhesive on the inner surfaces of the tank to establish the spaced apart relationship of the core and the tank.

4. A method as claimed in claim 3 in which all apertures in the inner side and bottom surfaces of the tank are sealed prior to the insertion of the synthetic resin mixture into the tank.

5. A method as claimed in claim 1 in which at least one wedge is inserted in the core to expand it causing its stepped perimetrical top edge to press firmly against the inner surfaces of the tank creating a perimetrical upper limit to the cavity and fixing the core in the tank.

6. A method for forming a synthetic resin lining on the inner sides and bottom surfaces of a toilet flush tank having a bottom, four side walls, and an open top comprising, the steps of inserting a self-expanding polyurethane mixture into the tank, placing an expansible core of the same general configuration as the tank having outer side and bottom surfaces and an outstanding perimetrical step at its top edge in which there is a vent, within and in spaced apart relationship to the tank to form a cavity between the inner surfaces of the tank and the outer surfaces of the core, allowing the poly-urethane mixture to expand to fill the cavity, and removing the core.

7. A method as claimed in claim 8 in which the core is covered with a parting agent prior to inserting it into the tank.

8. A method as claimed in claim 7 in which spacers are secured by means of adhesive on the inner surfaces of the tank to establish the spaced apart relationship of the core and the tank.

9. A method as claimed in claim 8 in which all apertures in the inner side and bottom surfaces of the tank are sealed prior to the insertion of the poly-urethane mixture into the tank.

10. A method as claimed in claim 9 in which at least one wedge is inserted in the core to expand it causing its stepped perimetrical top edge to press firmly against the inner surfaces of the tank creating a perimetrical upper limit to the cavity and fixing the core in the tank.

11. A method for forming a synthetic resin lining on the inner side and bottom surfaces of a toilet flush tank having a bottom, four side walls and an open top comprising the steps of covering with a parting agent an expansible core of the same general configuration as the tank having outer side and bottom surfaces and an outstanding perimetrical step at its top edge in which there is a vent, securing spacers to the inner surfaces of the tank, sealing all apertures in the inner side and bottom surfaces of the tank, inserting a self-expanding polyurethane mixture into the tank, positioning the core with in the tank so that the outer side and bottom surfaces of the core engage the spacers thus maintaining the core and tank in spaced apart relationship, inserting at least one wedge in the core to expand it causing its stepped perimetrical top edge to press firmly against the inner surfaces of the tank creating a perimetrical upper limit to the cavity and fixing the core in the tank, allowing the poly-urethane mixture to expand to fill the cavity, removing the wedging means and the core.

References Cited UNITED STATES PATENTS 3,013,922 12/1961 Fisher 26445 3,133,978 5/1964 Bartley et a1 264-45 3,158,906 12/1964 Bayer 249-183 XR FOREIGN PATENTS 663,979 5/ 1963 Canada.

PHILIP E. ANDERSON, Primary Examiner.

US. Cl. X.R. 

